Answer:
Crust
Step-by-step explanation:
According to the recently given theory, The theory of Seafloor Spreading the magma or lower most part of the earth's surface which sometimes bursts as (molten lava) plays substantial role in the formation of new crust. This is because when magma or molten lava from the bottom most part of the earth reaches the surface of earth, it cools down and pushes the already existing surface of the earth like rocks from both directions. This pushing of rocks cause the formation of new crust by the molten materials when it cools down.
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